Zetec Crank Position Sensor

[Sam M]

Hi, long time lurker.  Originally from the UK, I sold my 7 when I moved to Germany in 2015.  The itch never goes away though and I bought this 7 a couple of years ago on a whim, aware of a certain level of work needed to restore it to its former glory, but not appreciating it's not as easier to make time when you have 3 kids and some property. So earlier this year, after 18 months of failing to make time or find motivation, I admitted defeat and took it to a shop.

 

The work is nearing completion but the crank position sensor is weak.  However, the sensor is not the standard Ford one and points at a 60-2 trigger wheel rather than the standard 36-1.  Does anyone know if this was typical on US Zetecs?  Or recognize the type of sensor?

[11Budlite]

That has to be an aftermarket CPS. Perhaps it's a CPS that's used with the MegaSquirt ECU? The stock Ford one is located at the back left side of the block and reads off the flywheel. See attached photo.

[Scott_]

Seems to me that before replacing anything, the shop should put a scope on the sensor and check the air gap. I’d also have them pull the sensor and see if there are any identifying markings on it.

 

I’m fairly confident that 36-1 was Ford’s standard trigger arrangement for the Zetec, and the sensor and external trigger wheel in your photo certainly don’t look like the original Ford.

 

If you can establish whether it’s a Hall-effect or VR sensor, finding a replacement should be straightforward. But I’m curious what the shop means when they say the sensor is “weak.” Is the signal amplitude low, is it dropping out, or is the ECU having trouble recognizing it?  Ultimately, what matters is whether the ECU is receiving a clean, reliable signal of sufficient amplitude.

 

What kind of ECU do you have? If it’s a programmable aftermarket unit, I’d suggest having the shop find and download the appropriate software and connect a laptop. Depending on the ECU, they should be able to monitor engine speed, crank synchronization and other sensor inputs in real time. That might tell them (and you) quite a bit before they start replacing parts.

 

Also, have them check the trigger wheel for runout.   if it was damaged that could affect the signal.  Just a thought.

 

 

Scott

 

 

[pethier]

3 hours ago, 11Budlite said:

That has to be an aftermarket CPS. Perhaps it's a CPS that's used with the MegaSquirt ECU? The stock Ford one is located at the back left side of the block and reads off the flywheel. See attached photo.

My Caterham S3 has a 1995 Ford Contour Zetec.  Although it is running on a MegaSquirt ECU, it does indeed use the sensor at the back of the block.

 

I don't know a lot about these things, I do know that the location of the sensor (and perhaps the sensor itself) differs a little between the manual- and automatic-transmission cars.

 

I can't imagine why a location other than at the ring gear would be an improvement, but maybe someone can explain that to me.

[Sam M]

5 hours ago, Scott_ said:

I’m fairly confident that 36-1 was Ford’s standard trigger arrangement for the Zetec, and the sensor and external trigger wheel in your photo certainly don’t look like the original Ford.

 

If you can establish whether it’s a Hall-effect or VR sensor, finding a replacement should be straightforward. But I’m curious what the shop means when they say the sensor is “weak.” Is the signal amplitude low, is it dropping out, or is the ECU having trouble recognizing it?  Ultimately, what matters is whether the ECU is receiving a clean, reliable signal of sufficient amplitude.

 

What kind of ECU do you have? If it’s a programmable aftermarket unit, I’d suggest having the shop find and download the appropriate software and connect a laptop. Depending on the ECU, they should be able to monitor engine speed, crank synchronization and other sensor inputs in real time. That might tell them (and you) quite a bit before they start replacing parts.

 

 

Thanks Scott.  It's definitely not standard as it's a 60 tooth with 2 missing teeth design.  The shop inspected the flywheel through the standard CPS mount hole, and it looks like there are no trigger teeth on the flywheel, so looks like that's also a non-standard component.

 

The car came with a Megasquirt, but it was not an MS-3 Pro as per the advert, and the wiring was a bird's nest.  So a Haltech Nexus has now been fitted.  It will be going onto a rolling road once these issues have been resolved. The weak signal comment was 4th hand, as the dyno guy had remoted in to help diagnose (so with live data feed), and it was his recommendation to replace the sensor.  

 

Part of the issue is that there are no part numbers/marking on this sensor, and so I have no reference for the target air gap etc.  I will ask the shop if they can experiment with this a little, but at Bay Area hourly rates, replacing the sensor with something that has a known spec might actually be more cost effective!

[Sam M]

6 hours ago, 11Budlite said:

That has to be an aftermarket CPS. Perhaps it's a CPS that's used with the MegaSquirt ECU? The stock Ford one is located at the back left side of the block and reads off the flywheel. See attached photo.

The block has the mount hole in this position but the flywheel does not appear to have the trigger teeth, so looks to have been replaced at some point.

[redursidae]

How many wires are coming out of the sensor? 2 wires are reluctors (VR), 3 wires are Hall Effect. Can’t tell from the picture, but possibly the usual Hall Effect sensor used for MS installs: https://diyautotune.com/products/hall-effect-threaded-body-sensor

 

Haltech sells their own version as well (and cheaper?): https://www.haltech.com/product/ht-010610-red-single-channel-hall-effect-sensor

 

Using a Nexus really you just need something that’ll fit the threaded adapter and configure accordingly in the ECU. The beauty of standalones. Could also be a wiring issue considering your rats nest comment.

[1turbofocus]

" Weak " Sensor could also be the Gap sensor to pin distance isnt set properly also the TDC for the sensor to Pins isnt correct , there is a lot of adjustments to those Pickups , Focus-Power.com

Tom

[NSXguy]

An aftermarket/Standalone ecu cares little of which flavor (OEM vs aftermarket) VR sensor is feeding it or if the signal is picked up from the flywheel or crank as long as the sensor is in working order with correct gap and properly calibrated in the software. Therefore, all else being the same, if it was running before with Megasquirt, it should work with Haltech proper calibration. 

 

Also- An engine can be calibrated to run with a variety of crank trigger configurations(36-1, 60-2 etc). More teeth= better resolution, so if you're being told that you need to go back to the oem 36-1, that would be correct only if you were planning to run the standard ecu. The whole reason for running an aftermarket management is to untether yourself from the OEM configuration and unlock the full potential of the engine by using whatever hardware you desire. 

 

If you do find your current CPS to be faulty after thorough troubleshooting(ohm, check gap, scope trace etc), you can certainly use a standard Ford VR sensor that was offered on the late 90s contour, might need to make some small changes in the software to arming thresholds but that should be it. IIRC gap is ~ .75mm. Its the same CPS i'm using on my Emtron managed turbo car. 

-Dez

Edited Thursday at 12:16 AM by NSXguy

[wemtd]

I have an old Haltech sport but expect newer & other systems will similarly let you specify hall vs reluctor & tooth configuration. So as NSXguy noted you get to specify the setting. 
Basic thought is to also check continuity of wires in your loom… I had cryptic faults from by wiring issues discovered after lots of wasted sensor examinations & head scratching.